CN109567837B

CN109567837B - System and method for finite element analysis of bone-based DXA TOMO

Info

Publication number: CN109567837B
Application number: CN201811136869.3A
Authority: CN
Inventors: R·佩恩; P·马克沃特; S·穆勒
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 2017-09-29
Filing date: 2018-09-28
Publication date: 2024-08-02
Anticipated expiration: 2038-09-28
Also published as: US20190102877A1; CN109567837A; US10699405B2; EP3461412A1; JP7179541B2; JP2019063499A; EP3461412B1; KR102622708B1; KR20190038338A

Abstract

The imaging system uses 2D DXA images obtained during a tomographic imaging procedure or mode to provide more detailed information to an operator of the bone structure of a patient. The imaging system obtains a plurality of 2D DXA images at different angles with respect to the patient as the imaging system passes through the patient's body multiple times. These 2D DXA images may then be used to reconstruct at least one 2D slice of the patient's body, for example, in a plane parallel to the plane of a patient support surface, such as a scanner table. The information provided by the tomographic reconstruction provides an enhancement to the process of modifying the 3D FEA model, which is associated to a set of tomographic reconstructed slices that have been selected from a comparison with the current tomographic reconstructed slice that are already available. In this way, the system and method provide a significant reduction in error of the resulting modified 3D FEA model compared to the 2D method for viewing and analysis.

Description

System and method for finite element analysis of bone-based DXA TOMO

Technical Field

Background

Bone density or Bone Mineral Density (BMD) is the amount of bone mineral in bone tissue. This concept is the mass of mineral per bone volume (physically related to density), but clinically it is measured by proxy from the optical density per square centimeter of bone surface imaged. Bone density measurements are used in clinical medicine as an indirect indicator of osteoporosis and fracture risk. It is measured by a process called densitometry, typically performed in the radiology or nuclear medicine department of a hospital or clinic. The measurement is painless, non-invasive, involving low radiation exposure. Measurements are most commonly made on the lumbar spine and on the upper part of the hip. If the hip and lumbar spine are not accessible, the forearm may be scanned.

Body composition is represented by the portion of adipose tissue that makes up soft (non-mineral) tissue. Body composition is used in clinical medicine as an indirect indicator and/or risk factor for health conditions or diseases (sarcopenia, diabetes, obesity, etc.). Densitometry was also used to assess body composition. Most commonly measurements are made on the whole body or on the whole body except the head.

Leg and pelvis fractures due to falls are a significant public health problem, especially in older women, resulting in more medical costs, inability to live independently and even risk of death. Bone density measurements are used to screen people at risk of osteoporosis and identify those who may benefit from the measurements to improve bone strength.

Although there are many different types of BMD tests, all are non-invasive. Most tests differ in determining BMD results depending on which bones are measured. These tests include:

dual energy X-ray absorption assay (DXA or DEXA)

Double X-ray absorption assay and laser (DXL)

Quantitative Computed Tomography (QCT)

Quantitative Ultrasound (QUS)

Single photon absorption assay (SPA)

Two-photon absorption assay (DPA)

Digital X-ray radiographic Determination (DXR)

Single energy X-ray absorption measurement (SEXA)

DXA is currently in widespread use and works by measuring a specific bone or bones, typically the spine, hip and wrist. The density of these bones is then compared to an average index based on age, sex and body type. The comparison results produced are used to determine the risk of fracture and the stage of osteoporosis (if any) in the individual.

As illustrated in the exemplary embodiment in fig. 1, DXA scanner 100 comprises a table 102 for supporting a patient 101, and an X-ray source 104 (typically consisting of an X-ray generator, an X-ray tube, an X-ray filter and an X-ray collimator) is located in the table 102 and movable relative to the table 102 under the patient 101. In most embodiments of DXA system/scanner 100, detector 106 is disposed within arm 108 opposite detector 106 such that detector 106 and source 104 are positioned on opposite sides of patient 101. The detector 106 is primarily one-dimensional, but may be of two-dimensional or other suitably-dimensional configuration, and will be moved to capture X-ray photons emitted by the X-ray source 104 and passing through the patient's body 101. The arm 108 moves the detector 106 and is associated with the X-ray source 104, and the X-ray source 104 moves on the arm 108 in synchronization with the detector 106. Arm 108 moves both detector 106 and X-ray source 104 in a direction corresponding to the longer dimension of DXA table 102. In a DXA scanner that performs raster scanning (pencil beam or fan beam), both the detector 106 and the X-ray source 104 may be moved in a direction perpendicular to the longer dimension of the DXA table 102 in order to scan the table 102/body 101 along its width.

In an alternative embodiment, such as shown in FIG. 1, the table 102 includes an X-ray detector 106 disposed within the arm 108, spaced above the table 102, movable relative to the table 102. The table 102, along with the detector 106 and the X-ray source 104 and arm 108, may be operatively connected to a computer system 110, and the computer system 110 may control the operation of the X-ray source 104 and/or the arm 108 and may receive imaging data from the detector 106 generated by X-rays from the X-ray source 104 that pass through the patient 101 and strike the detector 106.

During DXA imaging, the scanner 100 moves the arm 108 and the X-ray source 104 along a body part of the patient 101 to be imaged in order to obtain a plurality of pairs (high energy and low energy) of two-dimensional (2D) DXA images of a specific part of the patient. DXA scanner 100 may move detector 106/X-ray source 104/arm 108 from head to foot along the body of patient 101 or along any portion of body 101 in order to obtain a desired DXA image. Depending on the type of beam generated by the X-ray source 104, e.g., pen-shaped, fan-shaped, or narrow fan-shaped (fig. 2A-2C), the X-ray source 104 and/or the detector 106 and/or the arm 108 may be moved directly along the main axis of the patient's body or in a raster scan mode in order to enable the X-ray source 104 and the detector 106 to image the entire body or a specific part of the body of the patient 101.

In performing DXA imaging, X-ray detector 106 generates dual energy (high energy (HE) and Low Energy (LE)) images of a particular portion of the body by detecting two different X-ray beams having different energy spectrums generated by X-ray source 104, or by detecting one X-ray beam generated from X-ray source 104 and discriminating between two different energy bins. There are 3 main ways to implement DXA:

Two X-ray beams of different energy spectra and a detector integrating the energy deposited by the emitted X-ray photons (photons passing through the body).

-One X-ray beam having a specific energy spectrum and a detector discriminating at least two energy beams of the emitted X-ray photons.

An X-ray beam with a specific energy spectrum and a detector consisting of at least two layers of detector elements, e.g. the upper layer will preferentially detect low energy photons and the lower layer will preferentially detect high energy photons.

One image is of high energy and the other image is of low energy. The X-ray beam passes through the patient 101 being scanned and contacts a detector 106 located on the scanner 100 opposite the X-ray source 104. The detector 106 is contacted by those X-rays that pass through the patient 101 but are not absorbed by the patient's tissue (bone and soft tissue), thus measuring the amount of X-rays that pass through the tissue from each beam. This will vary depending on the composition and thickness of the tissue. Based on the difference in the X-ray absorption of the two beams by the tissue, bone density and/or body composition can be measured.

In bone mineral density determinations, the scan results are analyzed and reported as average area bone mineral density BMD _a＝BMC/A[Kg/m², where BMC is the bone mineral content [ Kg ], and a is the projected area of the volume of the mixture containing bone mineral as part thereof [ m ² ]. Results are typically scored by both T-score and Z-score measurements. The Z-score represents the difference between the measured value BMD _a and an age-matched mean reference value normalized by the age-matched standard deviation of the overall variance in the individual subjects. The T score is similarly defined, but instead of an age-matched value, data from young reference populations is used. Based on the T scores developed by the WHO working group, the operational definition of osteoporosis has provided a unique BMD-based specific diagnostic criteria. WHO (1994) defines dividing subjects into one of four groups using an area BMD _a measured by DXA: normal (BMD _a T score ∈1.0); low bone mass or osteopenia (-1.0 > bmd _a T score > -2.5); osteoporosis (-2.5. Gtoreq. BMD _a T score); definitive osteoporosis (-2.5. Gtoreq. BMD _a T score) and at least one osteoporotic fracture.

For BMD, there are several limitations to using DXA. For example, since the calculation of bone density is only an approximation of bone strength based on the calculated mineral density of the bone, it is desirable to have an indication of stress and/or strain on the bone anywhere on the bone in order to provide a more direct indication of bone strength at these locations. One way to provide this bone strength analysis is to combine DXA images with finite element analysis to provide a more detailed representation of the bone density of the patient.

To assist in DXA images/procedures in determining BMD, in DXA, 2 images, namely a High Energy (HE) image and a Low Energy (LE) image, are typically generated. HE & LE images may be combined by software to generate one image of bone equivalent thickness and one image of soft tissue equivalent thickness. Other pairs of tissue equivalent images may be derived from the HE & LE images, providing material calibration derived from data acquired on a physical or simulated phantom made of sufficient material. In addition, only one of the 2 images (HE or LE, bone or soft tissue) may be used. In the illustrated exemplary embodiment of fig. 3, once the at least one 2D DXA image is obtained, using an appropriate computer system 110/50, the at least one DXA image 10 may be compared to a reference database 12 operatively connected to the computer system 50 or a stored 2D DXA image 14 contained on the computer system 50, in order to locate at least one stored 2D DXA image 14 that is most similar or identical to the at least one obtained 2D DXA image 10. One example of a system 50 and database 12 of this type is found in the 3D-DXA software package available from Galgo MEDICAL SL of Barcelona, spain, wherein the system 50 reconstructs a 3D form of bone structure from a 2D DXA image to evaluate the 3D form of femur shape, a bone shape, and the like from a DXA image according to Humbert L, MARTELLI Y, fonolla R et al 2017 at IEEE TRANS MED IMAGING 36:27-39 at 3D-DXA：Assessing the Femoral Shape,the Trabecular Macrostructure and the Cortex in 3D from DXA images(3D-DXA：, trabecular macrostructure and cortex) to evaluate cortical bone and trabecular macrostructure of bone in DXA image 10. The above-mentioned articles are expressly incorporated by reference in their entirety for all purposes. In this process, reference database 12 includes stored DXA images 14 and stored sets of CT scan images 18 previously obtained from other patients and corresponding to DXA images 14. The stored DXA images 14 and corresponding stored CT image sets 18 are used by the system 50 to construct a set of 3D Finite Element Analysis (FEA) models 20, the FEA models 20 also being stored in the database 12, each FEA model being associated with a CT scan image set 18 of each corresponding DXA image 14 and derivative model 20. When providing the system 50 with at least one obtained DXA image 10, the system 50 locates a 2D DXA image 14 that most closely resembles the at least one obtained 2D DXA image 10. The system 50 then locates the FEA model 20 associated with the particular stored DXA image 14 selected to be closest to the at least one obtained DXA image 10. The system 50 then modifies the FEA model 20 based on parameters from the at least one obtained 2D DXA image 10 to obtain a modified FEA model 20', the modified FEA model 20' illustrating on the model 20' different color maps of different parameters related to bone imaged with the DXA scanner providing the at least one DXA image 10, including but not limited to cortical thickness, cortical bulk density, and trabecular bulk density, among others.

Alternatively, as shown in fig. 4, the system 50 may be operated to calculate a stored 2D DXA image 16 associated with a particular CT scan image set 18 directly from the CT scan image set 18. These calculated 2D DXA images 16 are then compared with at least one obtained 2D DXA image 10 in the manner described previously to obtain a modified FEA model 20'.

However, while the process of obtaining the modified FEA model 20 'provides additional information about the bone structure in the at least one obtained 2D DXA image 10, the process for constructing the modified FEA model 20' still has significant drawbacks, as the at least one obtained 2D DXA image 10 contains a limited amount of information that can be used to modify the FEA model 20 and provide an accurate representation of the bone structure of the patient.

It is therefore desirable to provide imaging systems and methods for determining bone density and other associated parameters that provide an operator with enhanced volumetric imaging capabilities, thereby improving scan results and providing better measurements of bone density and strength.

Disclosure of Invention

There is a need or desire for an imaging system and associated method that is capable of obtaining an X-ray image of a patient's bone so as to enable the imaging system to provide an operator of the system with information regarding stress and/or strain present in the patient's bone in addition to other information regarding the bone (e.g., BMD). The imaging system uses 2D dual energy DXA images obtained during a tomographic imaging procedure or mode to provide more detailed information to an operator of a patient's bone structure. The imaging system obtains a plurality of 2D DXA images at different angles with respect to the patient in a single pass or multiple passes through the patient's body. These 2D DXA images can then be used to reconstruct at least one set of 2D slices (typically one (bone thickness) or two (HE/LE, bone/soft tissue)) of the patient's body in a plane generally parallel to the detector plane. The technical effect of the information provided by the tomographic reconstruction provides an enhancement to determining a correspondingly stored DXA image in a reference database, and a modification of a 3D FEA model corresponding to at least one selectively stored 2D DXA image for analyzing the structure of the bone/bone tissue of the patient/individual. In this way, the system and method provide a significant reduction in errors in the resulting modified 3D FEA model for viewing and analysis.

According to another aspect of the invention, a method for analyzing bone tissue in a patient, the method comprising the steps of: providing a scanning device comprising at least one X-ray source, at least one X-ray detector, and a controller for controlling movement of the at least one X-ray source and receiving image data from the at least one detector; operating the at least one X-ray source along at least one plane with respect to the patient to obtain a plurality of dual-energy X-ray images corresponding to a plurality of points, each point being positioned at a different angle with respect to an axis perpendicular to a detection surface of the at least one detector; reconstructing at least one two-dimensional (2D) planar slice image of bone tissue of the patient using the plurality of dual-energy X-ray images; and modifying a Finite Element Analysis (FEA) model with information provided by the at least one 2D planar slice image.

According to yet another aspect of the invention, a method of determining various parameters of bone within a patient's body, the method comprising the steps of: providing a scanning device comprising at least one X-ray source, at least one X-ray detector, and a controller for controlling movement of the at least one X-ray source and receiving image data from the at least one detector; operating the at least one X-ray source at a plurality of points along at least one plane relative to the patient to obtain a plurality of dual-energy X-ray images corresponding to the plurality of points, each point being positioned at a different angle relative to an axis perpendicular to a detection surface of the at least one detector; reconstructing at least one two-dimensional (2D) planar slice image of the patient using the plurality of dual-energy X-ray images; comparing the at least one 2D planar slice image to an image database operably connected to the controller; and modifying a Finite Element Analysis (FEA) model with information provided by the at least one 2D planar slice image.

According to yet another aspect of the invention, a method of determining various parameters of a patient, the method comprising the steps of: providing a scanning device comprising at least one X-ray source, at least one X-ray detector, and a controller for controlling movement of the at least one X-ray source and receiving image data from the at least one detector; operating the at least one X-ray source along at least one plane with respect to the patient to obtain a plurality of dual-energy X-ray images corresponding to a plurality of points, each point being positioned at a different angle with respect to an axis perpendicular to a detection surface of the at least one detector; reconstructing at least one two-dimensional (2D) planar slice image of the patient using the plurality of dual-energy X-ray images; segmenting the at least one 2D slice image into bone pixels and tissue pixels; and measuring the mass of tissue in the tissue pixels and the mass of tissue and bone mass in the bone pixels.

It should be understood that the brief description above is provided to introduce in simplified form a set of concepts that are further described in the detailed description. And is not intended to identify key or essential features of the claimed subject matter, the scope of which is defined solely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.

Drawings

The drawings illustrate the best mode contemplated for carrying out the invention. In the drawings:

Fig. 1 is a schematic representation of a DXA imaging system according to an exemplary embodiment of the invention.

Fig. 2A-2C are schematic illustrations of scan geometries of the DXA imaging system of fig. 1.

Fig. 3 is a schematic block diagram of a prior art image analysis system for use in conjunction with the DXA imaging system illustrated in fig. 1.

Fig. 4 is a schematic block diagram of a prior art image analysis system for use with the DXA imaging system illustrated in fig. 1.

Fig. 5 is a schematic diagram of a scanning method using the DXA imaging system of fig. 1, according to one embodiment of the invention.

FIG. 6 is a schematic block diagram of one embodiment of an image analysis system for use in conjunction with the scanning method of FIG. 5.

FIG. 7 is a schematic block diagram of one embodiment of an image analysis system for use in conjunction with the scanning method of FIG. 5.

FIG. 8 is a schematic block diagram of one embodiment of an image analysis system for use in conjunction with the scanning method of FIG. 5.

Fig. 9A-9B are schematic block diagrams of one embodiment of a prior art body composition image analysis system and a method for determining a body composition image analysis system in conjunction with the scanning method of fig. 5.

Detailed Description

In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments which may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments, and it is to be understood that other embodiments may be utilized and that logical, mechanical, electrical and other changes may be made without departing from the scope of the embodiments. The following detailed description is, therefore, not to be taken in a limiting sense.

Referring now to fig. 1, a dual energy X-ray absorptiometry (DXA) imaging system and/or scanner 100 according to an exemplary embodiment of the invention is illustrated. As previously described, DXA scanner 100 includes a table 102 for supporting a patient 101, and an x-ray source 104 is positioned in table 102 below patient 101. The table 102 also includes an X-ray detector 106 disposed within the arm 108, spaced above the table 102, movable with respect to the table 102. The positions of the X-ray source 104 and the detector 106 may also be reversed, if desired. The table 102, along with the detector 106 and the X-ray source 104 and arm 108, may be operatively connected to a computer system 110, and the computer system 110 may control the operation of the X-ray source 104 and/or the arm 108 and may receive imaging data from the detector 106 generated by X-rays from the X-ray source 104 that pass through the patient 101 and strike the detector 106.

Turning to fig. 1 and 5, the movement of the arm 108 and the operation of the X-ray source 104 and/or detector 106 when performing a scan to acquire X-ray projection data is managed by a control mechanism/computer system 110 of the DXA scanner 100. The control mechanism 110 includes an X-ray controller 112 and an arm motor controller 114, the X-ray controller 112 providing power and timing signals to the X-ray source 106, the arm motor controller 114 controlling the speed and position of the arm 108. A Data Acquisition System (DAS) 116 in the control mechanism 110 samples analog data from the detector 106 and converts the data to digital signals for subsequent processing when the detector is not transmitting direct digital signals. An image reconstructor 118 receives sampled and digitized X-ray data from DAS 116 and performs high-speed reconstruction. The reconstructed image is applied as an input to a computer 120, and the computer 120 stores the image in a database/mass storage device 122.

Moreover, the computer 120 may also receive commands and scanning parameters from an operator via an operator console 124 that may have an input device such as a keyboard 126. An associated display 128 allows the operator to view the reconstructed image and other data from the computer 120. The operator supplied commands and parameters are used by computer 120 to provide control signals and information to DAS 116, X-ray controller 112, and arm motor controller 114.

Referring now specifically to fig. 5, in one exemplary embodiment of the invention, the motion of the X-ray source 104 relative to the patient 101 and the detector 106 during a head-to-foot scan of the patient 101 is schematically illustrated. In contrast to the prior art scan path illustrated in fig. 2A-2C, the scanner 100 may be operated in a different tomographic imaging scan mode, such as in raster scanning, where the X-ray source 104 is at least partially moved along a plane perpendicular to the detector 106; in a scan in which the X-ray source 104 is moving at least partly in a continuous motion, wherein a temporally limited X-ray exposure may result in different dual-energy projections of the object being imaged, and/or the X-ray source 104 is moving at least partly perpendicular to the plane P, but in a more complex motion pattern than just planar motion, and optionally at varying distances from the detector 106, so as to be able to optimize image quality when reconstructing tomographic data from a set of projections obtained from different angles. In the illustrated exemplary embodiment of fig. 5, the X-ray source 104 moves along a plane or section W of the patient 101 oriented parallel to the entrance or detection surface 105 of the detector 106 and comes to rest, operating at varying angles between an axis passing through the centers of the X-ray source 104 and the detector 106 and an axis P at a plurality of positions, the axis P being centered on the detection surface 105 of at least one detector 106 and perpendicular to said detection surface 105. Once the desired number of images 129 have been obtained at this particular cross-section W of the patient 101, the arm 108 moves the source 104 and/or detector 106 to a different and possibly overlapping cross-section W in order to obtain additional images 129. This process is repeated a number of times until the patient 101 has been scanned sufficiently over the whole body or a particular part of the body. The plurality of imaging positions for the X-ray source 104 enables the X-ray source 104 to generate or obtain a plurality of images 129 of the same object (e.g., bone) within the patient 101 on the detector 106 at different angles relative to the plane P, wherein the images 129 may be dual energy images, i.e., low energy images and high energy images obtained from the patient 101 at each location where the X-ray source 104 is operated. In the DAS 116 and the image reconstructor 118, these images 129 can be reconstructed using tomography to form at least one set of 2D images 130,132 at different heights within the patient 101 that are parallel to the detector 106 or at other desired orientations relative to the detector 106.

In alternative exemplary embodiments, the scanner 100 may include a plurality of X-ray sources 104 spaced apart from one another along the arm 108. In operation, the individual X-ray sources 104 are sequentially operated to generate dual energy images 129 for tomographic reconstruction into a set 133 of 2D planar images 130,132 without moving the X-ray source 104 operating in a given plane perpendicular to the entrance surface of the detector 106. Thus, the presence and operation of multiple sources 104 may eliminate mechanically induced variations in the dual energy images 129 obtained between sources 104, as the sources 104 remain stationary during the process of obtaining each of the dual energy images 129.

Referring now to the exemplary embodiment illustrated in fig. 6, after the reconstruction of at least one set 133 of planar images 130,132 is completed, these images 130,132 may be compared, individually or collectively, to one or more stored sets of 2D tomographic scan images 134 obtained from DXA scans of other patients that remain within a database 122,136 operatively connected to the control mechanism 110. When the comparison results are close or similar between one or more obtained 2D tomographic images 130 and 132 in the set 133 and one or more stored 2D tomographic images in the DXA scan set of the tomosynthesis images 134, the control mechanism 110 may access the set of CT scan images 137 stored in the database 122,136 in association with the DXA scan set of a particular stored tomographic image 134 in order to generate or locate a stored 3D Finite Element Analysis (FEA) model 138 related to the selected set of images 134 and 137. Information from the collection 133 of acquired DXA tomographic images 130,132 is included in the FEA model 138 to construct a model 138', which model 138' may then be illustrated on the display 128 or other similar device operatively connected to the scanner 100, either as the model 138 is generated or as a modification to the model 138. In this way, the additional information provided by the at least one DXA tomographic image set 133 greatly reduces errors in constructing the model 138 and in representing the color maps of different parameters (e.g., cortical thickness, cortical bulk density, and trabecular bulk density, etc.) displayed on the model 138' and/or in evaluating the risk of fracture provided on or by the model 138.

Referring now to fig. 7, in an alternative embodiment of the invention, at least one set 133 of acquired DXA tomographic images 130,132 is compared to a stored set of computed DXA tomographic images 142 located in a database 122,136. These sets of computed DXA tomographic images 142 are reconstructed from a set of CT scan images 144 of an existing patient stored in the database 136 for comparison with at least one set 133 of acquired DXA tomographic images 130,132 and for forming the FEA model 138 from the set of stored CT scan images 144 and information from the acquired DXA scan tomographic images 130, 132. In the exemplary embodiment, no DXA scan has been previously performed on other patients because the DXA image 142 compared to the acquired set 133 of DXA scan tomographic images 130,132 is reconstructed directly from the CT scan image 144 of the patient, which CT scan image 144 of the patient is used to construct the model 138.

In another exemplary embodiment of the invention illustrated in fig. 8, at least one set 133 of acquired DXA scan tomographic images 130,132 is compared to a reformatted set of CT scan images 146, the reformatted set of CT scan images 146 being reconstructed from a set of CT scan images 148 obtained for an existing patient and stored in a database 122,136. The reformatted set of CT scan images 146 is an image reconstructed from a set of CT scan images 148, the set of CT scan images 148 corresponding to an image plane of at least one obtained DXA scan tomographic image 130,132, for example, along respective coronal planes of the patient. The selected reformatted image 146 is then used in combination with the CT scan image 148 and information from at least one set 133 of acquired DXA scan tomographic images 130,132 to generate the FEA model 138.

Referring now to fig. 9a, DXA scan image 150 is illustrated as being obtained using DXA scanner 10 and the scanning method illustrated in one of fig. 2A-2C. In image 150, each pixel 152 is analyzed based on whether pixel 152 is a bone pixel 154 or a soft tissue pixel 156, and is comprised of adipose tissue 158 and/or lean tissue 160 (muscle, non-adipose, and non-mineral tissue). In soft tissue pixels 156, the analysis measures adipose tissue portions 158 and lean tissue portions 160 from a combination of low energy DXA images and high energy DXA images. However, in bone pixel 154, since portions of three different materials (fat, lean, and bone) cannot be derived from only two images obtained at two different energies, it is assumed that the soft tissue composition within bone pixel 154 is similar to the soft tissue composition in adjacent soft tissue pixel 156, and the bone, fat, and lean tissue portions are derived accordingly. Once the analysis is completed, the values of the bone tissue portion, adipose tissue portion 158 and lean tissue portion 160 are summed over the whole body of the scanned individual and over the region of interest.

Referring now to fig. 9B, in another exemplary embodiment of the invention, body composition measurements are performed using DXA scanner 100 and an associated tomographic scanning method as schematically illustrated in fig. 5 to obtain a plurality of 2D tomographic slices 161 of a body or a region of interest within the body. As a result, although the individual pixels 162 in each of the tomographic images/slices 161 are similarly divided into the bone pixels 164 and the soft tissue pixels 166, since the volume evaluation of the adipose tissue portion 168 and the lean tissue portion 170 can be performed in each slice 160, the quantization of the adipose tissue portion 168 and the lean tissue portion 170 is more accurate, and as a result, more accurate results are obtained from the combination of the results of each slice 161.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. A method for analyzing bone tissue in a patient, the method comprising the steps of:

-providing a scanning device comprising at least one X-ray source, at least one X-ray detector and a controller for controlling the movement of the at least one X-ray source and receiving image data from the at least one detector;

-operating the at least one X-ray source at a number of points along at least one plane with respect to the patient to obtain a plurality of dual energy X-ray images corresponding to the number of points, each point being positioned at a different angle with respect to an axis perpendicular to the detection surface of the at least one detector;

-reconstructing at least one two-dimensional (2D) planar slice image of bone tissue of a patient using the plurality of dual-energy X-ray images; and

-Modifying a Finite Element Analysis (FEA) model with information provided by the at least one 2D planar slice image.

2. The method of claim 1, wherein operating the at least one X-ray source comprises:

-emitting X-rays from the at least one X-ray source at a first position relative to the detector to produce a first dual-energy X-ray image;

-moving the at least one X-ray source from the first position relative to the detector to a second position relative to the detector; and

-Emitting X-rays from the at least one X-ray source at the second position relative to the detector to produce a second dual-energy X-ray image.

3. The method of claim 1, wherein operating the at least one X-ray source comprises:

-emitting X-rays from a first X-ray source at a first position relative to the detector to produce a first dual-energy X-ray image; and

-Emitting X-rays from a second X-ray source at a second location spaced apart from the first X-ray source at the first location to produce a second dual-energy X-ray image.

4. The method of claim 1, wherein operating the at least one X-ray source comprises:

-emitting X-rays from the at least one X-ray source to produce a first number of dual-energy X-ray images along a first width of the patient;

-moving the X-ray source to a second width of the patient spaced apart from the first width; and

-Emitting X-rays from the at least one X-ray source to produce a second number of dual-energy X-ray images along the second width of the patient.

5. The method of claim 4, wherein reconstructing the at least one two-dimensional (2D) planar slice image comprises:

reconstructing a first 2D slice from the first and second number of dual energy X-ray images using tomography; and

-Reconstructing a second 2D slice from the first number and the second number of dual energy X-ray images with tomography.

6. A method of determining various parameters of bone within a patient's body, the method comprising the steps of:

-reconstructing at least one two-dimensional (2D) planar slice image of the patient using the plurality of dual-energy X-ray images;

-comparing the at least one 2D planar slice image with an image database operably connected to the controller; and

7. The method of claim 6, wherein the image database comprises a database of reconstructed 2D planar slice images.

8. The method of claim 6, wherein the image database comprises a database of reconstructed 2D planar slice images reconstructed from CT scan images.

9. The method of claim 6, wherein the image database comprises a database of reformatted CT scan images.

10. The method of claim 6, further comprising the step of:

-selecting one of the database-images; and

-Modifying a Finite Element Analysis (FEA) model associated with the selected database image using the reconstructed 2D planar slice image.

11. The method of claim 10, wherein modifying the Finite Element Analysis (FEA) model comprises changing parameters represented on the Finite Element Analysis (FEA) model.

12. The method of claim 11, wherein the step of changing parameters includes changing representations of parameters on the Finite Element Analysis (FEA) model.

13. The method of claim 12, wherein the step of changing the representation of the parameter comprises changing a color map provided on the Finite Element Analysis (FEA) model.

14. The method of claim 11, wherein the parameter is selected from the group consisting of: cortical thickness, cortical bulk density, and trabecular bulk density.

15. The method of claim 10, further comprising the step of: the Finite Element Analysis (FEA) model is formed with the selected database image and the CT scan images stored in the database in association with the selected database image prior to modifying the FEA model.

16. The method of claim 10, wherein the Finite Element Analysis (FEA) model is stored in association with the selected image in the database.